The basic goal of the projects are to elucidate the role of fluoride in metabolism during health and disease conditions and investigate the complex relation of fluoride intake to other trace elements (aluminum, zinc, copper, etc.) in biological system. In addition, the effect of fluoride on hormonal factors influencing calcified tissues and general metabolism is to be continued. The fluoride content of commerically available baby foods, factors influencing these levels, and fluoride intake of very young children will be determined. Studies of the possible relation in plasma of fluoride, zinc and copper concentrations to lipid metabolism and the influence of fluoride levels in culture medium on lipid metabolism of mice calvaria or isolated bone cells will be completed. The effect of fluoride intake on resorption of bone, bone and urine cAMP levels, and circulating parathormone levels will be continued employing calcium deficient-lactating rats. The influence of aluminum and zinc intake levels on intestinal fluoride absorption and bone fluoride levels and metabolism will be carried out. Studies on PTH levels in magnesium deficiency and sufficient rats, the role of the hormone in soft tissue calcification, and magnesium in stabilization of amorphous calcium phosphate in bone will be initiated. BIBLIOGRAPHIC REFERENCES: "Influence of Dietary Fluoride Restriction on Regulation of Plasma and Soft Tissue Fluoride Contents," Leon Singer, R.H. Ophaug, and W.D. Armstrong. Proc. Exper. Biol. and Med. 151, 627-631 (1976). "Effect of Fluoride on the Mobilization of Skeletal Magnesium and Soft-tissue Calcinosis during acute magnesium deficiency in the rat," R.H. Ophaug and Leon Singer. J. Nutr., 106, 771-777 (1976).